Grzegorz Janowski | Rzeszow University of Technology (original) (raw)

Papers by Grzegorz Janowski

Research paper thumbnail of Ocena możliwości wtryskiwania kompozytu WPC w produkcji elementów wyposażenia wnętrza autobusu w oparciu o symulacje numeryczne procesu

Research paper thumbnail of The Use of Computed Tomography in the Study of Microstructure of Molded Pieces Made of Poly(3-hydroxybutyric-co-3-hydroxyvaleric acid) (PHBV) Biocomposites with Natural Fiber

Polymers

In order to determine the structure homogeneity of biocomposites filled with fibers, as well as t... more In order to determine the structure homogeneity of biocomposites filled with fibers, as well as the evaluation of fibers’ arrangement and their orientation on the sample cross-section at varied injection rates, a study was conducted using computed tomography (CT). The main advantage of this test is the fact that in order to assess the microstructure on cross-sections, the samples do not have to be processed mechanically, which allows for presenting the actual image of the microstructure. The paper presents the issues of such tests for the biocomposite of poly (3-hydroxybutyric-co-3-hydroxyvaleric acid) (PHBV)-hemp fibers. It should be emphasized that CT scanning of PHBV-hemp fiber biocomposites is quite difficult to perform due to the similar density of the fibers and the polymer matrix. Due to the high difficulty of distinguishing fibers against the background of the polymer matrix during CT examination, a biocomposite containing 15% hemp fibers was analyzed. The samples for testin...

Research paper thumbnail of Biocomposites based on the poly(3-hydroxybutyrate-co-3-hydroxyvalerate) matrix with the hemp fibers: thermal and mechanical properties

Journal of Thermal Analysis and Calorimetry

The poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) was used to prepare biocompatible composi... more The poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) was used to prepare biocompatible composites modified by the hemp fibers. The aim of the study was to assess the structure and selected thermal and mechanical properties of the obtained biocomposites. The morphology of samples was analyzed using a scanning electron microscope and a computed tomography analysis. The phase transitions of composites and polymer matrix were investigated using differential scanning calorimetry. Moreover, the non-equilibrium and equilibrium thermal parameters of composites and the unfilled PHBV were established based on the thermal history. Knowing equilibrium parameters, i.e., the heat of fusion for the fully crystalline materials, ΔHf (100%), and the change of heat capacity at glass transition temperature (Tg) for the fully amorphous, ΔCp (100%), composites, the degree of crystallinity, mobile, and rigid amorphous fractions were estimated. The addition of hemp fibers to the PHBV matrix caused around a two-time increase in the degree of crystallinity in reference to the unfilled PHBV. It was also observed that the addition of hemp fibers caused a decrease in heat capacity for fully amorphous material for all the biocomposites obtained. A similar relationship was observed in case of values of the heat of fusion for fully crystalline material. Simultaneously, the decrease in amorphous phase contents was noted. It was also noted that the rigid amorphous fraction exists only for the unfilled polymer matrix. Some mechanical properties of investigated materials were also measured and presented.

Research paper thumbnail of Influence of Lifestyle on Prevention and Course of Diabetes

Nursing and Public Health

Research paper thumbnail of Advanced method of strength simulation of a WPC composite molding with orientation of fibers in polymer matrix considered

Research paper thumbnail of Characteristic of micro injection molding process. Molds, optimization of the process, application with specification to automotive industry

AUTOBUSY – Technika, Eksploatacja, Systemy Transportowe

The growing needs for miniaturization of plastic parts motivates to the development of micro inje... more The growing needs for miniaturization of plastic parts motivates to the development of micro injection molding technology. Characteristic features of this process such as: low manufacturing costs, short process duration, the ability to produce details of various dimensions and a wide range of plastic properties allow to mass dissemination of this technology. Research on micro injection molding develops in a very fast time, which gives high hopes for a successful overcoming of the real limitations of this technology. This gives a great perspective on the development of the possibility of using micro injection parts e.g. in the automotive industry. This paper presents the possibilities of manufacturing molds for micro injection molding. The issue of process optimization has been discussed, taking into consideration the main technological parameters influencing the quality of micro-part. In addition, the possibility of using microdetals, including the automotive industry was presented.

Research paper thumbnail of Ocena Wpływu Wyboru Modelu Mikromechanicznego Na Prognozowanie Orientacji Włókien Oraz Właściwości Mechaniczne Kompozytu WPC

Scientific Letters of Rzeszow University of Technology - Mechanics

Research paper thumbnail of Selected Properties of Biocomposites on the Basis of PHBV with Cellulose Fillers

Scientific Letters of Rzeszow University of Technology - Mechanics

Research paper thumbnail of The use of image analysis in evaluation of the fibers orientation in Wood-polymer composites (WPC)

Open Engineering

In this paper a novel way of a digital analysis of fibers orientation with a five-step algorithmw... more In this paper a novel way of a digital analysis of fibers orientation with a five-step algorithmwas presented. In the study, a molded piece with a dumbbell shape prepared from wood-polymer composite was used. The injection molding process was examined in experimental and numerical way. Based on the developed mathematical algorithm, a significant compliance of fiber orientation in different areas of the molded piece was obtained. The main aim of thisworkwas fiber orientation analysis of wood-polymer composites. An additional goal of thiswork was the comparison of the results reached in numerical analysis with results obtained from an experiment. The results of this research were important for the scientific and also from the practical point of view. In future works the prepared algorithm could be used to reach optimal parameters of the injection molding process.

Research paper thumbnail of The manufacturing issues of technical products made of polyimide – carbon fibers composite by means injection moulding process

Scientific Letters of University of Rzeszow Technology - Mechanics

Research paper thumbnail of Analysis of Fiber Orientation in the Wood-Polymer Composites (WPC) on Selected Examples

Advances in Science and Technology Research Journal

Research paper thumbnail of Łagodna symetryczna tłuszczakowatość typu II u 52-letniej pacjentki – opis przypadku i przegląd piśmiennictwa

Przegląd Medyczny Uniwersytetu Rzeszowskiego i Narodowego Instytutu Leków w Warszawie, 2015

Research paper thumbnail of Wykorzystanie programu Autodesk Moldflow® MPI w opracowaniu technologii RTM wytwarzania elementów kompozytowych

Scientific Letters of University of Rzeszow Technology - Mechanics, 2015

Research paper thumbnail of THE MANUFACTURING ISSUES OF TECHNICAL PRODUCTS MADE OF POLYIMIDE -CARBON FIBERS COMPOSITE BY MEANS INJECTION MOULDING PROCESS

Zeszyty Naukowe Politechniki Rzeszowskiej. Mechanika, 2016

Nowadays modern commercial simulation software provides acceptably faithful representation of rea... more Nowadays modern commercial simulation software provides acceptably faithful representation of reality, assuming the correctness of boundary conditions and reliability of data of processed composite material. In the case of non-standard plastics which include polyimide, we do not always have access to the target material and we do not have proper equipment to produce such products. Due to very interesting properties of the polyimide and its low popularity in use as an injection moulding material, the analysis of injection moulding of tooth plastic gear made from carbon fiber-polyimide composite was made. In this work the chosen material data, necessary for the numerical analysis, were presented. The impact analysis of main factors controlling the volumetric shrinkage during injection moulding processing was conducted. It was found that the greatest impact on the quality criterion is the melt temperature. To optimize control factors, the Taguchi orthogonal plans were used. In addition, the issue of polyimide properties, the possibility of its injection moulding and applications was discussed.

Research paper thumbnail of Selected aspects of manufacturing and strength evaluation of porous composites based on numerical simulations

Zeszyty Naukowe Politechniki Rzeszowskiej. Mechanika, 2017

In this paper the numerical simulations of microcellular injection molding process for polymer co... more In this paper the numerical simulations of microcellular injection molding process for polymer composite with glass fiber for variable content of pores were carried out. In order to evaluate the strength of the three-phase composite structure (poly-propylene PP as a matrix, 20% wt. of glass fiber GF and 1-9 % vol. of the pores) a microstructural analysis was performed and strength calculations were conducted using the Mori-Tanaka homogenization model. The analyzed product (the base of industrial mop) was subjected to the loading in Ansys 14.5 commercial code, considering the impact of pores content on its mechanical properties. Furthermore, the paper presents the visualization of calculated composite microstructure for variable pores contents.

Research paper thumbnail of Determination of viscosity curve and PVT properties for wood-polymer composite

Wood Research, 2018

In the presented study the injection mold equipped with the test apparatus were used to determine... more In the presented study the injection mold equipped with the test apparatus were used to determine the viscosity curve of wood – polymer – composite (WPC). During the test the polymer temperatures, flow rates and pressure data measured inside of mold cavity were recorded. In addition the pressure – volume – temperature (PVT) characteristic of this composite was determined using the capillary rheometer. The determined properties were used in numerical simulations of injection molding process of WPC. The results were verified on the basis of pressure profiles measured in the mold cavity during experiment. The simulation was performed using the Autodesk Moldflow Insight 2013 commercial code. The calculated and measured pressure profiles were compared.

Research paper thumbnail of Biocomposites based on the poly(3-hydroxybutyrate-co-3-hydroxyvalerate) matrix with the hemp fibers: thermal and mechanical properties

Journal of Thermal Analysis and Calorimetry, 2021

The poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) was used to prepare biocompatible composi... more The poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) was used to prepare biocompatible composites modified by the hemp fibers. The aim of the study was to assess the structure and selected thermal and mechanical properties of the obtained biocomposites. The morphology of samples was analyzed using a scanning electron microscope and a computed tomography analysis. The phase transitions of composites and polymer matrix were investigated using differential scanning calorimetry. Moreover, the non-equilibrium and equilibrium thermal parameters of composites and the unfilled PHBV were established based on the thermal history. Knowing equilibrium parameters, i.e., the heat of fusion for the fully crystalline materials, ΔHf (100%), and the change of heat capacity at glass transition temperature (Tg) for the fully amorphous, ΔCp (100%), composites, the degree of crystallinity, mobile, and rigid amorphous fractions were estimated. The addition of hemp fibers to the PHBV matrix caused around a two-time increase in the degree of crystallinity in reference to the unfilled PHBV. It was also observed that the addition of hemp fibers caused a decrease in heat capacity for fully amorphous material for all the biocomposites obtained. A similar relationship was observed in case of values of the heat of fusion for fully crystalline material. Simultaneously, the decrease in amorphous phase contents was noted. It was also noted that the rigid amorphous fraction exists only for the unfilled polymer matrix. Some mechanical properties of investigated materials were also measured and presented.

Research paper thumbnail of PREDICTING EFFECT OF FIBER ORIENTATION ON CHOSEN STRENGTH PROPERTIES OF WOOD-POLYMER COMPOSITES

COMPOSITES THEORY AND PRACTICE, 2019

The paper presents an assessment of the effect of fiber orientation on the strength properties of... more The paper presents an assessment of the effect of fiber orientation on the strength properties of products made from wood-polymer composites by the injection molding process based on micromechanical analysis. For this purpose numerical analysis was carried out for the product model with geometry of the sample intended for the uniaxial tensile test. To determine the actual fiber orientation after the manufacturing process, the orientation tensor values were calculated using Auto-desk Moldflow Insight 2016 software. The micromechanical calculations were performed using Digimat FE commercial code. The results (stress-strain characteristics) of the numerical simulations taking into account the calculated fiber orientation ten-sor were compared to the experiment. To produce the wood-polymer composite, the polypropylene polymer matrix was Moplen HP 648T. As the filler Lignocel C120 wood fibers made by Rettenmeier & Sohns company were applied. A composite with a 10 vol.% content of wood fibers in the polymer was manufactured in the extrusion process by means of a Zamak EHP 25 extruder. For specimen manufacturing a Dr. Boy 55E injection molding machine equipped with a two cavity injection mold was used. Before the numerical simulations the uniaxial tensile test was performed using a Zwick Roell Z030 testing machine. The specimens were tested at the speed of 50 mm/min according to the PN-EN ISO 527 standard. The obtained stress-strain characteristics were used as a verification criterion for further numerical analysis. Moreover, the mechanical properties of the same composite products were predicted for hypothetical fiber orientation types. It was noted that the selection of fiber orientation has a significant impact on the quality of the obtained results compared to the experiment. PROGNOZOWANIE WPŁYWU ORIENTACJI WŁÓKIEN NA WYBRANE WŁAŚCIWOŚCI WYTRZYMAŁOŚCIOWE KOMPOZYTÓW TYPU DREWNO-POLIMER Przedstawiono ocenę wpływu orientacji włókien na właściwości wytrzymałościowe wyrobów kompozytowych na przyk-ładzie wyrobów z kompozytu typu drewno-polimer formowanych w technologii wtryskiwania. Przeprowadzono analizę numeryczną dla modelu wyrobu o geometrii próbki przeznaczonej do próby jednoosiowego rozciągania. W celu uzyskania danych o powtryskowej orientacji włókien w matrycy polimerowej przeprowadzono analizę numeryczną procesu wtryski-wania za pomocą oprogramowania Autodesk Moldflow Insigth 2016. Uzyskano w ten sposób wartości tensora orientacji włókien dla zadanych parametrów technologicznych procesu wytwarzania wyrobu. Obliczenia mikromechaniczne (analizy właściwości struktury kompozytu) przeprowadzono z wykorzystaniem oprogramowania Digimat FE. Wyniki analizy numerycznej dla obliczonej wartości tensora orientacji włókien porównano z eksperymentem. Ponadto, w celu ułatwienia definiowania w systemach CAE właściwości kompozytu wykonano prognozowanie jego właściwości mechanicznych dla hipo-tetycznych, uproszczonych przypadków orientacji włókien. Potwierdzono, iż dobór orientacji napełniacza (włókien) ma zna-czący wpływ na zgodność prognozowanych właściwości kompozytu z wynikami badań eksperymentalnych.

Research paper thumbnail of FIBER SHAPE SELECTION PROBLEMS IN MATERIAL MODELS USED IN NUMERICAL STRENGTH ANALYSIS OF WOOD-POLYMER COMPOSITES

COMPOSITES THEORY AND PRACTICE, 2019

The paper presents the problems in selecting the fiber shape in numerical strength analysis for w... more The paper presents the problems in selecting the fiber shape in numerical strength analysis for wood-polymer composites. For this purpose numerical analysis of the uniaxial tensile test for the wood-polymer composite sample was performed. Variable geometry of the fiber model was used. The fiber orientation data were obtained using Autodesk Moldflow Insight 2016 software. Micromechanical calculations based on homogenization methods were performed using Digimat FE commercial code. The results of the numerical simulations were compared with the experiment ones. To manufacture the WP composite , Moplen HP 648T polypropylene (PP) from Basell Orlen Polyolefins was used as the polymer matrix. As the filler 10 vol.% Lignocel C120 wood fiber manufactured by JRS-J. RETTENMAIER & Söhne Company was used. Adhesion promoter P613 by Dupont was used as well. A Dr Boy 55E injection molding machine was used to produce the test specimens. It was noted that the selection of the fiber shape has a significant impact on the consistency of the obtained results and consequently on compliance with the experiment ones. Fiber location calculations were performed for each geometry type available in the Digimat software. The most consistent results for numerical homogenization (Digimat FE) are associated with the choice of a curved cylinder shape of fiber. This may be due to the greatest convergence of the orientation tensor value received from the numerical simulation of the injection molding process during its transformations to the representative volume element model. In addition, this result may be due to the fact that the curved cylinder type of geometry is characterized by the most variable shape due to the degree of curvature. This reflects the real, non-standard problems to determine the shape of the wood fiber in the polymer matrix.

Research paper thumbnail of INFLUENCE OF RVE GEOMETRICAL PARAMETERS ON ELASTIC RESPONSE OF WOVEN FLAX- EPOXY COMPOSITE MATERIALS

COMPOSITES THEORY AND PRACTICE, 2020

In the case of polymer composites reinforced with natural fiber woven fabrics, microstructural ca... more In the case of polymer composites reinforced with natural fiber woven fabrics, microstructural calculations are extremely difficult to perform due to their characteristic variability, among others their mechanical properties. The aforementioned scientific problem has not been thoroughly investigated, hence the purpose of this work was to assess the possibilities of predicting the properties of a composite reinforced with flax woven fabric by micromechanical calculations using the Mori-Tanaka and the double inclusion homogenization models. In addition, the second important utilitarian problem that was undertaken in the work was assessment of the impact of the size of the representative volume element (RVE) on the obtained results. The analyses were carried out for composites based on epoxy resin reinforced with flax fabrics: plain, 2x2 twill and 3x1 twill types. Based on the performed calculations, it was found that the obtained results depend on the type of weave in the fabric used, the size of the RVE, the number of yarn bands in the RVE and the appropriately selected homogenization method. Guidelines useful for evaluating the optimal RVE size depending on the type of weave were formulated. WPŁYW PARAMETRÓW GEOMETRYCZNYCH W REO NA WŁAŚCIWOŚCI SPRĘŻYSTE MATERIAŁÓW KOMPOZYTOWYCH ŻYWICA EPOKSYDOWA-TKANINA LNIANA W przypadku kompozytów polimerowych zbrojonych tkaninami z włókien naturalnych przeprowadzanie obliczeń mikro-strukturalnych jest wyjątkowo trudne do wykonania z uwagi na charakterystyczną dla nich zmienność, m.in. właściwości me-chanicznych. Wspomniany problem naukowy nie jest dokładnie zbadany, stąd celem niniejszej pracy była ocena możliwości prognozowania właściwości kompozytu wzmacnianego tkaniną lnianą poprzez obliczenia mikromechaniczne z wykorzysta-niem modelu homogenizacji Mori-Tanaka oraz Double Inclusion. Ponadto drugim istotnym problemem utylitarnym, który podjęto w pracy, była ocena wpływu wielkości reprezentatywnego elementu objętościowego (REO) na uzyskane wyniki. Ana-lizy przeprowadzono dla kompozytów o osnowie żywicy epoksydowej zbrojnej tkaninami lnianymi o splocie: płóciennym, sko-śnym 2x2 oraz skośnym 3x1. Na podstawie przeprowadzonych obliczeń stwierdzono, że uzyskane wyniki zależą od rodzaju splotu w zastosowanej tkaninie, wielkości REO, ilości pasm przędzy w REO oraz odpowiednio dobranej metody homogeniza-cji. Sformułowano wskazówki przydatne do oceny optymalnego wymiaru REO w zależności od rodzaju splotu. Słowa kluczowe: REO, kompozyty wypełnione włóknami naturalnymi, Digimat, len, MES, homogenizacja

Research paper thumbnail of Ocena możliwości wtryskiwania kompozytu WPC w produkcji elementów wyposażenia wnętrza autobusu w oparciu o symulacje numeryczne procesu

Research paper thumbnail of The Use of Computed Tomography in the Study of Microstructure of Molded Pieces Made of Poly(3-hydroxybutyric-co-3-hydroxyvaleric acid) (PHBV) Biocomposites with Natural Fiber

Polymers

In order to determine the structure homogeneity of biocomposites filled with fibers, as well as t... more In order to determine the structure homogeneity of biocomposites filled with fibers, as well as the evaluation of fibers’ arrangement and their orientation on the sample cross-section at varied injection rates, a study was conducted using computed tomography (CT). The main advantage of this test is the fact that in order to assess the microstructure on cross-sections, the samples do not have to be processed mechanically, which allows for presenting the actual image of the microstructure. The paper presents the issues of such tests for the biocomposite of poly (3-hydroxybutyric-co-3-hydroxyvaleric acid) (PHBV)-hemp fibers. It should be emphasized that CT scanning of PHBV-hemp fiber biocomposites is quite difficult to perform due to the similar density of the fibers and the polymer matrix. Due to the high difficulty of distinguishing fibers against the background of the polymer matrix during CT examination, a biocomposite containing 15% hemp fibers was analyzed. The samples for testin...

Research paper thumbnail of Biocomposites based on the poly(3-hydroxybutyrate-co-3-hydroxyvalerate) matrix with the hemp fibers: thermal and mechanical properties

Journal of Thermal Analysis and Calorimetry

The poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) was used to prepare biocompatible composi... more The poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) was used to prepare biocompatible composites modified by the hemp fibers. The aim of the study was to assess the structure and selected thermal and mechanical properties of the obtained biocomposites. The morphology of samples was analyzed using a scanning electron microscope and a computed tomography analysis. The phase transitions of composites and polymer matrix were investigated using differential scanning calorimetry. Moreover, the non-equilibrium and equilibrium thermal parameters of composites and the unfilled PHBV were established based on the thermal history. Knowing equilibrium parameters, i.e., the heat of fusion for the fully crystalline materials, ΔHf (100%), and the change of heat capacity at glass transition temperature (Tg) for the fully amorphous, ΔCp (100%), composites, the degree of crystallinity, mobile, and rigid amorphous fractions were estimated. The addition of hemp fibers to the PHBV matrix caused around a two-time increase in the degree of crystallinity in reference to the unfilled PHBV. It was also observed that the addition of hemp fibers caused a decrease in heat capacity for fully amorphous material for all the biocomposites obtained. A similar relationship was observed in case of values of the heat of fusion for fully crystalline material. Simultaneously, the decrease in amorphous phase contents was noted. It was also noted that the rigid amorphous fraction exists only for the unfilled polymer matrix. Some mechanical properties of investigated materials were also measured and presented.

Research paper thumbnail of Influence of Lifestyle on Prevention and Course of Diabetes

Nursing and Public Health

Research paper thumbnail of Advanced method of strength simulation of a WPC composite molding with orientation of fibers in polymer matrix considered

Research paper thumbnail of Characteristic of micro injection molding process. Molds, optimization of the process, application with specification to automotive industry

AUTOBUSY – Technika, Eksploatacja, Systemy Transportowe

The growing needs for miniaturization of plastic parts motivates to the development of micro inje... more The growing needs for miniaturization of plastic parts motivates to the development of micro injection molding technology. Characteristic features of this process such as: low manufacturing costs, short process duration, the ability to produce details of various dimensions and a wide range of plastic properties allow to mass dissemination of this technology. Research on micro injection molding develops in a very fast time, which gives high hopes for a successful overcoming of the real limitations of this technology. This gives a great perspective on the development of the possibility of using micro injection parts e.g. in the automotive industry. This paper presents the possibilities of manufacturing molds for micro injection molding. The issue of process optimization has been discussed, taking into consideration the main technological parameters influencing the quality of micro-part. In addition, the possibility of using microdetals, including the automotive industry was presented.

Research paper thumbnail of Ocena Wpływu Wyboru Modelu Mikromechanicznego Na Prognozowanie Orientacji Włókien Oraz Właściwości Mechaniczne Kompozytu WPC

Scientific Letters of Rzeszow University of Technology - Mechanics

Research paper thumbnail of Selected Properties of Biocomposites on the Basis of PHBV with Cellulose Fillers

Scientific Letters of Rzeszow University of Technology - Mechanics

Research paper thumbnail of The use of image analysis in evaluation of the fibers orientation in Wood-polymer composites (WPC)

Open Engineering

In this paper a novel way of a digital analysis of fibers orientation with a five-step algorithmw... more In this paper a novel way of a digital analysis of fibers orientation with a five-step algorithmwas presented. In the study, a molded piece with a dumbbell shape prepared from wood-polymer composite was used. The injection molding process was examined in experimental and numerical way. Based on the developed mathematical algorithm, a significant compliance of fiber orientation in different areas of the molded piece was obtained. The main aim of thisworkwas fiber orientation analysis of wood-polymer composites. An additional goal of thiswork was the comparison of the results reached in numerical analysis with results obtained from an experiment. The results of this research were important for the scientific and also from the practical point of view. In future works the prepared algorithm could be used to reach optimal parameters of the injection molding process.

Research paper thumbnail of The manufacturing issues of technical products made of polyimide – carbon fibers composite by means injection moulding process

Scientific Letters of University of Rzeszow Technology - Mechanics

Research paper thumbnail of Analysis of Fiber Orientation in the Wood-Polymer Composites (WPC) on Selected Examples

Advances in Science and Technology Research Journal

Research paper thumbnail of Łagodna symetryczna tłuszczakowatość typu II u 52-letniej pacjentki – opis przypadku i przegląd piśmiennictwa

Przegląd Medyczny Uniwersytetu Rzeszowskiego i Narodowego Instytutu Leków w Warszawie, 2015

Research paper thumbnail of Wykorzystanie programu Autodesk Moldflow® MPI w opracowaniu technologii RTM wytwarzania elementów kompozytowych

Scientific Letters of University of Rzeszow Technology - Mechanics, 2015

Research paper thumbnail of THE MANUFACTURING ISSUES OF TECHNICAL PRODUCTS MADE OF POLYIMIDE -CARBON FIBERS COMPOSITE BY MEANS INJECTION MOULDING PROCESS

Zeszyty Naukowe Politechniki Rzeszowskiej. Mechanika, 2016

Nowadays modern commercial simulation software provides acceptably faithful representation of rea... more Nowadays modern commercial simulation software provides acceptably faithful representation of reality, assuming the correctness of boundary conditions and reliability of data of processed composite material. In the case of non-standard plastics which include polyimide, we do not always have access to the target material and we do not have proper equipment to produce such products. Due to very interesting properties of the polyimide and its low popularity in use as an injection moulding material, the analysis of injection moulding of tooth plastic gear made from carbon fiber-polyimide composite was made. In this work the chosen material data, necessary for the numerical analysis, were presented. The impact analysis of main factors controlling the volumetric shrinkage during injection moulding processing was conducted. It was found that the greatest impact on the quality criterion is the melt temperature. To optimize control factors, the Taguchi orthogonal plans were used. In addition, the issue of polyimide properties, the possibility of its injection moulding and applications was discussed.

Research paper thumbnail of Selected aspects of manufacturing and strength evaluation of porous composites based on numerical simulations

Zeszyty Naukowe Politechniki Rzeszowskiej. Mechanika, 2017

In this paper the numerical simulations of microcellular injection molding process for polymer co... more In this paper the numerical simulations of microcellular injection molding process for polymer composite with glass fiber for variable content of pores were carried out. In order to evaluate the strength of the three-phase composite structure (poly-propylene PP as a matrix, 20% wt. of glass fiber GF and 1-9 % vol. of the pores) a microstructural analysis was performed and strength calculations were conducted using the Mori-Tanaka homogenization model. The analyzed product (the base of industrial mop) was subjected to the loading in Ansys 14.5 commercial code, considering the impact of pores content on its mechanical properties. Furthermore, the paper presents the visualization of calculated composite microstructure for variable pores contents.

Research paper thumbnail of Determination of viscosity curve and PVT properties for wood-polymer composite

Wood Research, 2018

In the presented study the injection mold equipped with the test apparatus were used to determine... more In the presented study the injection mold equipped with the test apparatus were used to determine the viscosity curve of wood – polymer – composite (WPC). During the test the polymer temperatures, flow rates and pressure data measured inside of mold cavity were recorded. In addition the pressure – volume – temperature (PVT) characteristic of this composite was determined using the capillary rheometer. The determined properties were used in numerical simulations of injection molding process of WPC. The results were verified on the basis of pressure profiles measured in the mold cavity during experiment. The simulation was performed using the Autodesk Moldflow Insight 2013 commercial code. The calculated and measured pressure profiles were compared.

Research paper thumbnail of Biocomposites based on the poly(3-hydroxybutyrate-co-3-hydroxyvalerate) matrix with the hemp fibers: thermal and mechanical properties

Journal of Thermal Analysis and Calorimetry, 2021

The poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) was used to prepare biocompatible composi... more The poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) was used to prepare biocompatible composites modified by the hemp fibers. The aim of the study was to assess the structure and selected thermal and mechanical properties of the obtained biocomposites. The morphology of samples was analyzed using a scanning electron microscope and a computed tomography analysis. The phase transitions of composites and polymer matrix were investigated using differential scanning calorimetry. Moreover, the non-equilibrium and equilibrium thermal parameters of composites and the unfilled PHBV were established based on the thermal history. Knowing equilibrium parameters, i.e., the heat of fusion for the fully crystalline materials, ΔHf (100%), and the change of heat capacity at glass transition temperature (Tg) for the fully amorphous, ΔCp (100%), composites, the degree of crystallinity, mobile, and rigid amorphous fractions were estimated. The addition of hemp fibers to the PHBV matrix caused around a two-time increase in the degree of crystallinity in reference to the unfilled PHBV. It was also observed that the addition of hemp fibers caused a decrease in heat capacity for fully amorphous material for all the biocomposites obtained. A similar relationship was observed in case of values of the heat of fusion for fully crystalline material. Simultaneously, the decrease in amorphous phase contents was noted. It was also noted that the rigid amorphous fraction exists only for the unfilled polymer matrix. Some mechanical properties of investigated materials were also measured and presented.

Research paper thumbnail of PREDICTING EFFECT OF FIBER ORIENTATION ON CHOSEN STRENGTH PROPERTIES OF WOOD-POLYMER COMPOSITES

COMPOSITES THEORY AND PRACTICE, 2019

The paper presents an assessment of the effect of fiber orientation on the strength properties of... more The paper presents an assessment of the effect of fiber orientation on the strength properties of products made from wood-polymer composites by the injection molding process based on micromechanical analysis. For this purpose numerical analysis was carried out for the product model with geometry of the sample intended for the uniaxial tensile test. To determine the actual fiber orientation after the manufacturing process, the orientation tensor values were calculated using Auto-desk Moldflow Insight 2016 software. The micromechanical calculations were performed using Digimat FE commercial code. The results (stress-strain characteristics) of the numerical simulations taking into account the calculated fiber orientation ten-sor were compared to the experiment. To produce the wood-polymer composite, the polypropylene polymer matrix was Moplen HP 648T. As the filler Lignocel C120 wood fibers made by Rettenmeier & Sohns company were applied. A composite with a 10 vol.% content of wood fibers in the polymer was manufactured in the extrusion process by means of a Zamak EHP 25 extruder. For specimen manufacturing a Dr. Boy 55E injection molding machine equipped with a two cavity injection mold was used. Before the numerical simulations the uniaxial tensile test was performed using a Zwick Roell Z030 testing machine. The specimens were tested at the speed of 50 mm/min according to the PN-EN ISO 527 standard. The obtained stress-strain characteristics were used as a verification criterion for further numerical analysis. Moreover, the mechanical properties of the same composite products were predicted for hypothetical fiber orientation types. It was noted that the selection of fiber orientation has a significant impact on the quality of the obtained results compared to the experiment. PROGNOZOWANIE WPŁYWU ORIENTACJI WŁÓKIEN NA WYBRANE WŁAŚCIWOŚCI WYTRZYMAŁOŚCIOWE KOMPOZYTÓW TYPU DREWNO-POLIMER Przedstawiono ocenę wpływu orientacji włókien na właściwości wytrzymałościowe wyrobów kompozytowych na przyk-ładzie wyrobów z kompozytu typu drewno-polimer formowanych w technologii wtryskiwania. Przeprowadzono analizę numeryczną dla modelu wyrobu o geometrii próbki przeznaczonej do próby jednoosiowego rozciągania. W celu uzyskania danych o powtryskowej orientacji włókien w matrycy polimerowej przeprowadzono analizę numeryczną procesu wtryski-wania za pomocą oprogramowania Autodesk Moldflow Insigth 2016. Uzyskano w ten sposób wartości tensora orientacji włókien dla zadanych parametrów technologicznych procesu wytwarzania wyrobu. Obliczenia mikromechaniczne (analizy właściwości struktury kompozytu) przeprowadzono z wykorzystaniem oprogramowania Digimat FE. Wyniki analizy numerycznej dla obliczonej wartości tensora orientacji włókien porównano z eksperymentem. Ponadto, w celu ułatwienia definiowania w systemach CAE właściwości kompozytu wykonano prognozowanie jego właściwości mechanicznych dla hipo-tetycznych, uproszczonych przypadków orientacji włókien. Potwierdzono, iż dobór orientacji napełniacza (włókien) ma zna-czący wpływ na zgodność prognozowanych właściwości kompozytu z wynikami badań eksperymentalnych.

Research paper thumbnail of FIBER SHAPE SELECTION PROBLEMS IN MATERIAL MODELS USED IN NUMERICAL STRENGTH ANALYSIS OF WOOD-POLYMER COMPOSITES

COMPOSITES THEORY AND PRACTICE, 2019

The paper presents the problems in selecting the fiber shape in numerical strength analysis for w... more The paper presents the problems in selecting the fiber shape in numerical strength analysis for wood-polymer composites. For this purpose numerical analysis of the uniaxial tensile test for the wood-polymer composite sample was performed. Variable geometry of the fiber model was used. The fiber orientation data were obtained using Autodesk Moldflow Insight 2016 software. Micromechanical calculations based on homogenization methods were performed using Digimat FE commercial code. The results of the numerical simulations were compared with the experiment ones. To manufacture the WP composite , Moplen HP 648T polypropylene (PP) from Basell Orlen Polyolefins was used as the polymer matrix. As the filler 10 vol.% Lignocel C120 wood fiber manufactured by JRS-J. RETTENMAIER & Söhne Company was used. Adhesion promoter P613 by Dupont was used as well. A Dr Boy 55E injection molding machine was used to produce the test specimens. It was noted that the selection of the fiber shape has a significant impact on the consistency of the obtained results and consequently on compliance with the experiment ones. Fiber location calculations were performed for each geometry type available in the Digimat software. The most consistent results for numerical homogenization (Digimat FE) are associated with the choice of a curved cylinder shape of fiber. This may be due to the greatest convergence of the orientation tensor value received from the numerical simulation of the injection molding process during its transformations to the representative volume element model. In addition, this result may be due to the fact that the curved cylinder type of geometry is characterized by the most variable shape due to the degree of curvature. This reflects the real, non-standard problems to determine the shape of the wood fiber in the polymer matrix.

Research paper thumbnail of INFLUENCE OF RVE GEOMETRICAL PARAMETERS ON ELASTIC RESPONSE OF WOVEN FLAX- EPOXY COMPOSITE MATERIALS

COMPOSITES THEORY AND PRACTICE, 2020

In the case of polymer composites reinforced with natural fiber woven fabrics, microstructural ca... more In the case of polymer composites reinforced with natural fiber woven fabrics, microstructural calculations are extremely difficult to perform due to their characteristic variability, among others their mechanical properties. The aforementioned scientific problem has not been thoroughly investigated, hence the purpose of this work was to assess the possibilities of predicting the properties of a composite reinforced with flax woven fabric by micromechanical calculations using the Mori-Tanaka and the double inclusion homogenization models. In addition, the second important utilitarian problem that was undertaken in the work was assessment of the impact of the size of the representative volume element (RVE) on the obtained results. The analyses were carried out for composites based on epoxy resin reinforced with flax fabrics: plain, 2x2 twill and 3x1 twill types. Based on the performed calculations, it was found that the obtained results depend on the type of weave in the fabric used, the size of the RVE, the number of yarn bands in the RVE and the appropriately selected homogenization method. Guidelines useful for evaluating the optimal RVE size depending on the type of weave were formulated. WPŁYW PARAMETRÓW GEOMETRYCZNYCH W REO NA WŁAŚCIWOŚCI SPRĘŻYSTE MATERIAŁÓW KOMPOZYTOWYCH ŻYWICA EPOKSYDOWA-TKANINA LNIANA W przypadku kompozytów polimerowych zbrojonych tkaninami z włókien naturalnych przeprowadzanie obliczeń mikro-strukturalnych jest wyjątkowo trudne do wykonania z uwagi na charakterystyczną dla nich zmienność, m.in. właściwości me-chanicznych. Wspomniany problem naukowy nie jest dokładnie zbadany, stąd celem niniejszej pracy była ocena możliwości prognozowania właściwości kompozytu wzmacnianego tkaniną lnianą poprzez obliczenia mikromechaniczne z wykorzysta-niem modelu homogenizacji Mori-Tanaka oraz Double Inclusion. Ponadto drugim istotnym problemem utylitarnym, który podjęto w pracy, była ocena wpływu wielkości reprezentatywnego elementu objętościowego (REO) na uzyskane wyniki. Ana-lizy przeprowadzono dla kompozytów o osnowie żywicy epoksydowej zbrojnej tkaninami lnianymi o splocie: płóciennym, sko-śnym 2x2 oraz skośnym 3x1. Na podstawie przeprowadzonych obliczeń stwierdzono, że uzyskane wyniki zależą od rodzaju splotu w zastosowanej tkaninie, wielkości REO, ilości pasm przędzy w REO oraz odpowiednio dobranej metody homogeniza-cji. Sformułowano wskazówki przydatne do oceny optymalnego wymiaru REO w zależności od rodzaju splotu. Słowa kluczowe: REO, kompozyty wypełnione włóknami naturalnymi, Digimat, len, MES, homogenizacja